Irbil , Iraq -LRB- CNN -RRB- They take sledgehammers to statues with an uncommon gusto -- destroying in seconds what may have survived centuries .

New video released by ISIS shows militants smashing what they say are antiquities at a museum in Mosul , Iraq .

Men shove statues off pedestals , and use hammers and drills to destroy what 's left .

An unnamed militant offers the following explanation : `` These antiquities and idols behind me were from people in past centuries and were worshiped instead of God .

`` When God Almighty orders us to destroy these statues , idols and antiquities , we must do it , even if they 're worth billions of dollars , '' he says .

It 's not clear from the footage how many of the pieces were originals , versus replicas . Experts are clear in saying , however , the video represents a clear loss .

Qais Hussain Rashid , director general of Iraqi museums at the Ministry of Antiquities and Tourism , said Friday on Iraqiya TV that most of the artifacts shown in the ISIS video were real -- including a famed , millennia-old winged bull that 's seen being defaced with a drill .

`` Mosul Museum has 173 original pieces , and there were preparations to reopen the Mosul Museum before ISIS invaded the city in June 2014 , '' Rashid said .

He added that Mosul has more than 1,700 historical sites that are potentially at risk .

`` On repeated viewing of that very grainy video , we now suspect that there -LRB- were -RRB- far more originals in the museum than I first thought , '' said Eleanor Robson , chairwoman of the British Institute for the Study of Iraq .

`` Whilst there was indeed a program to relocate antiquities to safekeeping in Baghdad , it looks now as though it did n't reach that particular museum . ''

`` I condemn this as a deliberate attack against Iraq 's millennial history and culture , and as an inflammatory incitement to violence and hatred , '' said Irina Bokova , director-general of UNESCO , the United Nations cultural organization .

`` This attack is far more than a cultural tragedy -- this is also a security issue as it fuels sectarianism , violent extremism and conflict in Iraq , '' she said , calling for an emergency meeting of the Security Council to protect Iraq 's cultural heritage .

How ISIS is run

CNN has extensively reported on ISIS ' destruction of some ancient and deeply meaningful sites in that country . Officials there have said ISIS has blown up shrines such as the tomb of Jonah .

Its motives are not purely ideological , however ; ISIS makes money off looting .

Rashid has told CNN that ISIS sells stolen antiquities to criminals and antique dealers on the black market .

Everything to know about the rise of ISIS

The militant group also allows locals to dig at ancient sites as long as those people give ISIS a percentage of the monetary value of anything found , according to a September 2014 New York Times opinion piece written by three people who had recently returned from southern Turkey and interviewed people who live and work in ISIS-controlled territory .

ISIS ' system of profiteering from antiquities thieving is very complicated , the three said , adding that for some areas along the Euphrates River , ISIS leaders encourage semiprofessional field crews to dig .

ISIS militant ` Jihadi John ' identified

Ben Wedeman reported this story from Irbil . Dana Ford reported and wrote this story from Atlanta . CNN 's Ashley Fantz and Yousuf Basil also contributed to this report .

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Director general of Iraqi museums says Mosul Museum had 173 original pieces

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It 's not clear from the footage how many of the pieces were originals , versus replicas

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UNESCO chief : `` This attack is far more than a cultural tragedy -- this is also a security issue as it fuels sectarianism ''